A color filter is one of key elements for colorization of a Liquid Crystal Display (LCD). Specifically, through the color filter, strong light rays emitted by a backlight module of the LCD can be converted into a colorful picture. With respect to fabricating a color filter, a black matrix is to be disposed on a glass substrate in form of grids, and then color blocking elements for three primary colors, i.e., Red (R), Green (G), and Blue (B), are arranged on respective pixel units defined by the black matrix in turn.
As shown in FIG. 1, when fabricating a black matrix, it is usually to coat black photoresist on a glass substrate 01 to form a photoresist layer 02. And then, as shown in FIG. 2, exposure and developing processes are performed on the photoresist layer 02 using a mask 03. Finally, as shown in FIG. 3, a black matrix 04 is obtained and retained on the glass substrate 01.
Insofar as a black matrix having a line width of around 5 μm can be achieved, when the line width thereof is reduced further, many deforms or malfunctions may occur, including a reaction happened due to a large-area contact between black matrix photoresist and developer, a film/layer peel-off occurrence, uneven edges, and so on. Nevertheless, as products having high Pixels Per Inch (PPI) are prevailing in the market, a black matrix having a line width of around 5 μm can hardly meet the requirements for LCD products in terms of transmittance ratio and aperture ratio. Therefore, it is a highly demanding job to come up with a solution about how to fabricate a black matrix pattern having a narrow line width.